iio: dac: add NXP LPC18xx DAC driver
Add base support for the 10-bit DAC peripheral found on NXP LPC18xx/43xx SoCs. This is a minimal driver that does not support DMA or interrupts. User manual with register description can be found on: LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf Signed-off-by: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Joachim Eastwood
Jonathan Cameron
parent
edcb2d26c1
commit
9bbccbe11a
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@ -154,6 +154,16 @@ config AD7303
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To compile this driver as module choose M here: the module will be called
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ad7303.
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config LPC18XX_DAC
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tristate "NXP LPC18xx DAC driver"
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depends on ARCH_LPC18XX || COMPILE_TEST
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depends on OF && HAS_IOMEM
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help
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Say yes here to build support for NXP LPC18XX DAC.
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To compile this driver as a module, choose M here: the module will be
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called lpc18xx_dac.
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config M62332
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tristate "Mitsubishi M62332 DAC driver"
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depends on I2C
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@ -17,6 +17,7 @@ obj-$(CONFIG_AD5764) += ad5764.o
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obj-$(CONFIG_AD5791) += ad5791.o
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obj-$(CONFIG_AD5686) += ad5686.o
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obj-$(CONFIG_AD7303) += ad7303.o
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obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
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obj-$(CONFIG_M62332) += m62332.o
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obj-$(CONFIG_MAX517) += max517.o
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obj-$(CONFIG_MAX5821) += max5821.o
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@ -0,0 +1,210 @@
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/*
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* IIO DAC driver for NXP LPC18xx DAC
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*
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* Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* UNSUPPORTED hardware features:
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* - Interrupts
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* - DMA
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*/
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/driver.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/consumer.h>
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/* LPC18XX DAC registers and bits */
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#define LPC18XX_DAC_CR 0x000
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#define LPC18XX_DAC_CR_VALUE_SHIFT 6
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#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff
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#define LPC18XX_DAC_CR_BIAS BIT(16)
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#define LPC18XX_DAC_CTRL 0x004
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#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3)
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struct lpc18xx_dac {
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struct regulator *vref;
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void __iomem *base;
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struct mutex lock;
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struct clk *clk;
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};
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static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {
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{
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.type = IIO_VOLTAGE,
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.output = 1,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
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BIT(IIO_CHAN_INFO_SCALE),
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},
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};
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static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct lpc18xx_dac *dac = iio_priv(indio_dev);
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u32 reg;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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reg = readl(dac->base + LPC18XX_DAC_CR);
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*val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;
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*val &= LPC18XX_DAC_CR_VALUE_MASK;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = regulator_get_voltage(dac->vref) / 1000;
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*val2 = 10;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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return -EINVAL;
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}
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static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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struct lpc18xx_dac *dac = iio_priv(indio_dev);
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u32 reg;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)
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return -EINVAL;
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reg = LPC18XX_DAC_CR_BIAS;
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reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;
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mutex_lock(&dac->lock);
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writel(reg, dac->base + LPC18XX_DAC_CR);
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writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);
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mutex_unlock(&dac->lock);
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return 0;
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}
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return -EINVAL;
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}
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static const struct iio_info lpc18xx_dac_info = {
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.read_raw = lpc18xx_dac_read_raw,
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.write_raw = lpc18xx_dac_write_raw,
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.driver_module = THIS_MODULE,
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};
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static int lpc18xx_dac_probe(struct platform_device *pdev)
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{
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struct iio_dev *indio_dev;
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struct lpc18xx_dac *dac;
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struct resource *res;
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int ret;
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indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
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if (!indio_dev)
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return -ENOMEM;
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platform_set_drvdata(pdev, indio_dev);
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dac = iio_priv(indio_dev);
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mutex_init(&dac->lock);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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dac->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(dac->base))
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return PTR_ERR(dac->base);
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dac->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(dac->clk)) {
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dev_err(&pdev->dev, "error getting clock\n");
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return PTR_ERR(dac->clk);
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}
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dac->vref = devm_regulator_get(&pdev->dev, "vref");
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if (IS_ERR(dac->vref)) {
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dev_err(&pdev->dev, "error getting regulator\n");
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return PTR_ERR(dac->vref);
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}
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indio_dev->name = dev_name(&pdev->dev);
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indio_dev->dev.parent = &pdev->dev;
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indio_dev->info = &lpc18xx_dac_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = lpc18xx_dac_iio_channels;
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indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);
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ret = regulator_enable(dac->vref);
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if (ret) {
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dev_err(&pdev->dev, "unable to enable regulator\n");
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return ret;
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}
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ret = clk_prepare_enable(dac->clk);
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if (ret) {
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dev_err(&pdev->dev, "unable to enable clock\n");
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goto dis_reg;
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}
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writel(0, dac->base + LPC18XX_DAC_CTRL);
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writel(0, dac->base + LPC18XX_DAC_CR);
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ret = iio_device_register(indio_dev);
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if (ret) {
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dev_err(&pdev->dev, "unable to register device\n");
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goto dis_clk;
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}
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return 0;
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dis_clk:
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clk_disable_unprepare(dac->clk);
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dis_reg:
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regulator_disable(dac->vref);
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return ret;
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}
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static int lpc18xx_dac_remove(struct platform_device *pdev)
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{
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struct iio_dev *indio_dev = platform_get_drvdata(pdev);
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struct lpc18xx_dac *dac = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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writel(0, dac->base + LPC18XX_DAC_CTRL);
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clk_disable_unprepare(dac->clk);
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regulator_disable(dac->vref);
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return 0;
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}
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static const struct of_device_id lpc18xx_dac_match[] = {
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{ .compatible = "nxp,lpc1850-dac" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);
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static struct platform_driver lpc18xx_dac_driver = {
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.probe = lpc18xx_dac_probe,
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.remove = lpc18xx_dac_remove,
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.driver = {
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.name = "lpc18xx-dac",
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.of_match_table = lpc18xx_dac_match,
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},
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};
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module_platform_driver(lpc18xx_dac_driver);
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MODULE_DESCRIPTION("LPC18xx DAC driver");
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MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
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MODULE_LICENSE("GPL v2");
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